Apparatus for mixing and blending materials, some of which are in a finely divided state



Sept. 22, 1942. sMl H r 2,296,581

APPARATUS FOR MIXING AND BLENDING MATERIALS, SOME OF WHICH ARE IN A FINELY DIVIDED STATE Filed May 6, 1941 FIG.2

Iuvuu-rofifi ALFRFD B- MI CLIFFORD R. SMITH ATTORNEY Patented Sept. 22, 1942 UNITED STATES PAT FIETE' Alfred Bartlett Smith and Clifford Ross-Smith, Wolverhampton, England Application May 6, 1941, Serial No. 392,164 In Great Britain May 6,1940- 4 Claims.

The invention relates to the art of mixing and blending solid materials some ofwhich are in a finely divided state, such as the mixing togetherof sands, and the blending of thesewith a binder such as cil, molasses, bonding compounds and finally divided clays for core-making and other foundry purposes.

In an earlier patent specification, No. 1,751,221, apparatus is disclosed in which such materials in addition to being thrown and rolled about by moving arms or sweeps are squeezed through wedge-like pockets or spaces formed by the cooperating members of the apparatus.

In the present invention the output of an apparatus for a given diameter of container is considerably increased by'combining with such a tossing and squeezing action, a cascading action in the course of which a large part of the charge in the container, carried round in front of a moving arm or sweep, rides up asmooth inclined plane on the leading edge of the member forming the squeezing pocket and over a crest and down a rear face of the member and falls to the bottom of the container in the void temporarily caused beyond each pocket by the passage of the last moving member to force the material through that particular pocket. Thepart of the charge which has passed over the upper part of the pocket-forming member is encountered and forced around and through the next pocket by the mass in front of the next arm or sweep.

The mass in front of each arm or sweep as it clears a pocket thus encounters and forces around such fallen material, which at the next pocket is forced in part through the pocket and in part up over the inclined surfaces forming the leading and rear edges of the pocket-forming member, and these motions occasion such a high degree of intermixture and frictional contact of the component particles, that a much larger mass than could be treated through the pockets in a given time in a particular size of machine can be given the required degree of mixing and blend- Apparatus in accordance with the invention thus has a pan or container with arms moving in the pan or container along the bottom thereof, pocket-forming members arranged in the pan above the bottom with their lower surfaces inclined to the bottom of the pan so as to form in conjunction therewith the desired wedge-like pockets, the upper surfaces of these pocket-formfall in a'broken condition to-the floor of the container.

The wall of the container will be of greater depth than the highest part of the ridge of the vpocket-forming member was to contain the material which is passing up and being thrown over the member.

The apparatus may most conveniently be'made as a rotary apparatus in' which an arm or arms rotate in a cylindrical cup-like panwh'ich has a flat base, and'in this cup-like container a plurality of fixed pocketand' weir-forming members are arranged projecting inwardly from the pan wall so that their inclined end surfaces allow the rotary arms or sweeps to pass beneath'them, the longitudinal axis of these members being backwardly raked from the true radial position in the cup-like container. It is preferred that the upper surfaces of each pocketand weirforming member shall be oppositely inclined faces and that the ridge between these inclines near the root' of the member at the pan wall shall be a concave curve'relatively to the movement of the arm or sweep, and that the innermost end shall. be convexly curved relative to such moving arm or sweep.

In the appended. drawing a preferred embodiment of construction is illustrated, in which Figure 1 is a plan;

Figure 2 is a vertical section, and

Figure 3 is a developed or strip sectional view showing the relationship of the arms or sweeps andthe pocket-forming members to each otherand to the wall and base of the pan.

In the drawing the construction of the pan or and the means for driving the arms or sweeps b may follow closely on the lines set forth in the specification of the Patent 1,751,221 previously referred to. Four arms or sweeps b areshown with rearwardly inclined leading faces c,.the front edge of which curves backward slightly towards the outer end of the arm and the whole of which arm is raked back slightly from the true radial position relatively to the axis of rotation at d. The rotary arms or sweeps b are disposed in the lower part of the pan a so that their lower edges are just clear of the base or floor of the pan e. 7 Over the upper end of the drive shaft f for the arms or sweeps b is a central distributing dome or spreader g, as in the apparatus described in the aforementioned patent specification.

Pocket-forming members, which are connected to the inner wall of the-container a and which "extend inwardly therefrom, operate in conjunction'with the arms or sweeps b and are referredto in'general by th letter h. The letter 1' refers to the inclined lower surface. which forms in' conjunction with the base e of the pan the wedge-like pocket through which the arms or sweeps I) travel. The leading edge :1 of each pocket-forming member h is rearwardly inclined from its junction with the under surface 2' to a ridge or crest k, and fromthis ridge or crest is a downwardly inclined rear face m which is continued to the rear edge of the under surface i, all of which is clearly shown in the developed sectional view, Figure 3, which shows the section of the pocket-forming member h at about the middle of its length from the pan wall to the inwardly directed end. The leading face of the member :1 which is toward the on-coming arms 17 is concavely curved at its root as at n and convexly curved towards its free extremity as at o in Figure 1.

As the arms or sweeps b are rotated in the pan, material in the pan is carried round in front of their inclined front faces and as each pocket-forming member I; is approached by an arm, part of the material is forced through the wedge-like pocket below the member h as in the apparatus set forth in the patent specification referred to. The part of the material which tends to rise on the inclined leading face of the arm I) is lifted up on to the rearwardly inclined leading face a of the member h and is pushed up that face and over the crest to fall down the reversely inclined rear face m. The time taken by the materials so caused to pass over the weirlike upper part of the pocket-forming members it is such that the arm 12 has passed through the pocket before the material which has passed over the weir falls from the rear edge m thereof. This material therefore falls in broken condition into a void on the pan base and is encountered by the material pushed round in front of the next arm and is forced by it around the pan and through and part of it over the next pocketforming member I; as before set forth.

The concave face at n on the arm h tends to direct the material climbing up this face at the top of the ridge inwardly away from the pan wall so as to prevent any tendency for it to rise up out of the pan.

The invention is not limited to application to apparatus in which the pocket-forming members h are fixed to the wall of the pan, since if desired the squeezing pockets may be formed by the co-operation with the base of the container of moving members travelling oppositely to the arms or sweeps, but an arrangement in which these members are fixed is much preferred since it makes for the simplicity and durability of the structure.

The members h can be cast with attachment faces or lugs on their roots into which attachment studs or bolts passing through the pan wall can be threaded.

We claim:

1. Apparatus for mixing and blending finely divided solid material with a finder comprising in combination a cylindrical container, an arm rotatable in the container along the bottom thereof, a member attached to the wall of the container and extending radially inwardly therefrom and having its lower surface above and inclined to the bottom of the container so as to form in conjunction therewith a wedge-like pocket, said member having its longitudinal axis inclined from the true radial position in the container in the direction of movement of said moving arm, said member having upper surfaces which are smooth and respectively upwardly and downwardly inclined in the direction of movement of the moving arm, the surface on the leading face rising up to a longitudinal ridge and that on the rear face extending down from said longitudinal ridge to the rear edge of the inclined under surface of said pocket-forming member.

2. Apparatus for mixing and blending finely divided solid material with a binder comprising in combination a cylindrical container, an arm rotatable in the container along the bottom thereof, a member broad at the root and narrow at the tip attached at the root to the wall of the container and extending radially inwardly therefrom and having its lower surface above and inclined to the bottom of the container so as to form in conjunction therewith a wedge-like pocket in which said finely divided solid material and binder are squeezed as said arm moves into and through the pocket, said member having its longitudinal axis inclined from the true radial position in the container in the direction of movement of said moving arm and having upper surfaces which are smooth and inclined in the direction of movement of the moving arm, the surface on the leading face rising up to a longitudinal ridge and that on the rear face extending down from said longitudinal ridge to the rear edge of the inclined under surface of the member, the surface of the leading face of the member being concavely curved adjacent its radially outermost end and convexly curved adjacent its radially innermost end in order that the finely divided material will be directed, while cascading over the member, towards the center of the container.

3. Apparatus for mixing and blending finely divided solid material with a binder comprising in combination a cylindrical container, an arm rotatable in the container along the bottom thereof, a member broad at the root and narrow at the tip attached at the root to the wall of the container and extending radially inwardly therefrom to the central confines of the container and having its lower surface above and inclined to the bottom of the container so as to form in conjunction therewith a wedge-like pocket in which said finely divided solid material and binder are squeezed as said arm moves into and through the pocket, said member having its longitudinal axis inclined from the true radial position in the container in the direction of movement of said moving arm and having upper surfaces which are smooth and inclined in the direction of movement of the moving arm, the surface on the leading face rising up to a longitudinal ridge and that on the rear face extending down from said longitudinal ridge to the rear edge of the inclined under surface of the member, the surface of the leading face of the member being concavely curved adjacent its radially outermost end and convexly curved adjacent its radially innermost end, the longitudinal ridge being curved, in the direction of movement of the arm, from its outermost part adjacent the container wall to its innermost end.

4. Apparatus for mixing and blending finely divided solid material with a binder according to claim 2, in which the clearance between the rotatable arm and the rear edge of the under surface of the member is small in order to provide an optimum squeezing action.

ALFRED BARTLETT SMITH. CLIFFORD ROSS SMITH. 

